Silver salt diffusion transfer processes are well known in the art. For example, silver salt diffusion transfer processes are described in A. Rott and E. Weyde, Photographic Silver Halide Diffusion Processes, Focal Press, London (1972); J. Stutge, V. Walworth and A. Shepp, Imaging Processes and Materials: Neblette's Eighth Edition, Vol. 8, Chapter 6, Instant Photography and Related Reprographic Processes, Van Nostrand Reinhold (1989); and G. Haist, Modern Photographic Processing, Vol. 2, Chapter 8, Diffusion Transfer, John Wiley and Sons.
Many kinds of photographic materials can be prepared by the diffusion transfer processes. Namely, it is known that a light-sensitive element in which a silver halide emulsion is applied to a support and an image receiving element in which an image receiving layer containing silver precipitation nuclei is applied to another support are superimposed on each other, and an alkaline processing composition such as a high viscosity or low viscosity alkaline processing composition containing a developing agent and a silver halide solvent, i.e., a processing element, is developed between the two elements described above, whereby a transfer image can be obtained. In practicing the present invention, this photographic material described above is advantageously used.
Another photographic material is known in which a light-sensitive layer and an image receiving layer are applied to the same support, one over the other, and a positive image can be observed through a negative image, utilizing the high covering power of the positive image, as described in U.S. Pat. No. 2,861,885. Further, a photographic material is known in which materials similar to those described above are used where the light-sensitive layer is washed out after diffusion transfer processing to obtain a positive image alone.
Furthermore, another photographic material is known in which a light-sensitive layer of a silver halide, a layer containing a light reflection material such as titanium white, and an image receiving layer containing silver precipitation nuclei are applied to a support, one over the other in this order, and processed, whereby a positive image can be obtained. Moreover, a photographic material is also known in which a light-sensitive element and an image receiving element are integrally laminated on a support, and subjected to diffusion transfer processing, whereby it can be used without separation of the light-sensitive element and the image receiving element. These photographic materials are described in detail in the literature described above.
It is widely desired to reduce the time for formation of images utilizing the silver salt diffusion transfer processes. One method for reducing the time for formation of images encompasses increasing the amount of a developing agent. According to this method, however, metallic luster is developed on the images, the images become reddish in color tone, and the images deteriorate with respect to storage quality, in particular fading quality.
Another method encompasses increasing the amount of silver halide dissolving agent. This method is however undesirable because metallic luster is developed on the images and the images become bluish.
In addition, another method encompasses increasing the amount of silver applied. However, this method has the disadvantages of lowered sensitivity and difficulty in terminating the reaction at the late stage of transfer.
A further method encompasses reducing the thickness of a spacer of an image receiving sheet for determining the developing thickness of processing element to shorten the diffusion transfer distance. According to this method, however, the images are deteriorated in density unevenness, and manufacturing and processing suitability is also lost.
Thus, in the various methods seeking to reduce the time for forming images, many disadvantages result.